This invention relates to a rotary motor, and more particularly, the invention relates to a motor that utilizes linear actuators to effect low speed, high torque rotation.
Vehicles typically use internal combustion engines for their sole propulsion means. There has been increasing pressure to use alternative propulsion systems or supplemental propulsion systems to the traditional combustion system to reduce vehicle emissions. To this end, electric motors have been used as a supplemental or substitute system to the combustion engine.
Electric motors used in vehicle applications typically include a rotor and stator arrangement that results in a high motor output shaft speed. Motors using a rotor and stator arrangement characteristically cannot produce high torque at low speeds without stalling. Accordingly, gear reduction boxes are coupled between the motor and vehicle wheel end to reduce the speed and increase the torque to the wheel. However, the gear reduction boxes add expense to the vehicle, in particular for vehicles that primarily require high torque at low speeds. Therefore, what is needed is an electric motor that produces high torque at low speeds without requiring a gear reduction box.
The present invention provides an electric motor assembly that includes a housing. A rotor is arranged in the housing and is rotatable about an axis. A vehicle wheel is coupled to the rotor. The rotor has an annular profile defining sinusoidal teeth and is generally concentric with the axis. The angle and number of oblique surfaces of the teeth and the diameter of the rotor, in part, define the sped and torque of the rotor. A plurality of electric linear actuators are arranged circumferentially about and generally parallel to the axis. The actuator includes shafts having ends that engage the profile. The shafts are movable between extended and retracted positions to rotate the rotor in a desired direction. A sensor detecting the position of the rotor and a controller may be used to effect the desired rotation.
Accordingly, the above invention provides an electric motor that produces high torque at low speeds without requiring a gear reduction box.